If the Supremes were somehow to decide that neither candidate was…
If the Supremes were somehow to decide that neither candidate was Constitutionally eligible, then the Electoral College would be absolutely free to choose the candidate of their choice, without regard to any pledges they made at the election. It would work the same way that the EC worked in the very first Presidential election, when they all chose George Washington because *they* thought he would make a good President, not because anyone had told them to. This notion of running slates of elector-candidates pledged to vote for one candidate or another was an invention of Thomas Jefferson for the election of 1800.